Power tool

ABSTRACT

A power tool ( 2 ) includes a motor ( 22 ) pivotally mounted within the housing of the tool. The tool is able to accept any one of a plurality of attachment members ( 32 ). The motor ( 22 ) is adapted to pivot in order that accurate axial alignment with any one of the attachment members presented to the motor occurs.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a power tool and has particularalthough not exclusive, relevance to battery powered tools.

2. Description of the Related Art

It is conventional for power tools to be designed and built for adedicated purpose, such as a drill, a jigsaw or a sander. If the userneeds to undertake a sanding operation he will use a dedicated sander.If then he needs to drill a hole in a workpiece he will swap the sanderfor a dedicated drill, and so on.

Whilst such swapping over of dedicated tools is not inconvenient, itdoes mean that, particularly for the person who needs to use power toolsrelatively infrequently, considerable expense is incurred in acquiring abroad range of these dedicated power tools.

Furthermore, in the case of so-called “cordless” or battery-poweredtools, the user will either need to change the battery pack whenchanging dedicated tools, or have several ready-charged batteriesavailable for use. These alternative options are cumbersome or expensiverespectively.

Solutions to the above problems have been proposed in the past and onesuch solution entails providing a power tool including a motorised drivewhich is capable of accepting any one of a plurality of discreteattachments which achieve a dedicated purpose. This means that ratherthan purchasing a dedicated entire power tool for each job, the useronly has to purchase a dedicated attachment (which is cheaper than adedicated entire tool) and just swap these over as and when necessary.

There still exist certain problems with such solutions, however. In asystem such as the discreet attachments described above, it is importantto achieve a high degree of alignment between the body of the toolproviding the drive and the attachment which receives the drive. In thecase of a rotational drive such as a drive shaft, a high degree of axialalignment between the driving and driven shafts is imperative in orderto achieve an efficient transfer of energy between the two and also toavoid creating unnecessary mechanical wearing at the interface betweenthe shafts.

BRIEF SUMMARY OF THE INVENTION

It is an object of the present invention to at least alleviate theaforementioned shortcomings by providing a power tool including a bodyportion defining a handle and a motor mounted within the body portion,which motor is arranged to drive an output spindle of the tool; the bodyportion further defining an opening around the output spindle, whichopening accepts any one of a plurality of attachment members presentedthereto, the power tool characterised in that the motor is mountedwithin the housing by aplurality of supports spaced along the axiallength of the motor and wherein at least one of the supports of theplurality does not rigidly contact the motor, thereby to permit themotor to move within its mounting. Thus, by enabling the motor of thebody portion of the tool to move, a high degree of axial and positionalalignment between the output spindle of the motor and the rotationaldrive of the attachment may be achieved because this degree of movementpermits of automatic co-axial alignment between the two parts.

Preferably at one end of the axial length of the motor a plurality ofsupports make rigid contact therewith and at the other end of the axiallength of the motor at least one of the supports of the plurality do notrigidly contact the motor thereby allowing themotor to pivot about thepoint at which it is in rigid contact with the said supports. Byprovision of pivoting movement of the motor, the amount of movement, or“play” exhibited by the motor may be limited and have any unnecessarymovement avoided. Additionally or alternatively the motor, at either endof its axial length, is formed in circular cross-section and thesupports of the plurality are found therearound. This shape permits amethod of construction of the power tool which is relatively easy toassemble.

In a preferred embodiment the plurality of supports is formed from, orintegrally with, the body portion itself.

Also the body portion may be formed in two halves which two halves cometogether and thereby encapsulate the motor therewithin.

Furthermore movement of the motor within the housing, relative to anattachment member, when presented to the tool, is prevented. Also themotor may itself, be connected to the output spindle.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will now be described, by way of example only andwith reference to the accompanying drawings, of which:

FIG. 1 shows a front perspective view of a body portion of a power toolin accordance with the present invention;

FIG. 2 shows a part cut-away view of the body portion of FIG. 1;

FIG. 3 shows a side part-sectioned view of the body portion of FIG. 1without an attachment member presented thereto;

FIG. 4 shows a side part-sectioned view of the body portion of FIG. 1with an attachment member presented thereto;

FIG. 5 shows an end-on part cut-away view of FIG. 4;

FIG. 6 shows a side view of one of the plurality of attachment membersto be presented to the body portion. This is a drill/driver mechanismfor a drill;

FIG. 7 shows an alternative attachment to FIG. 6, this being a jigsawattachment, and;

FIG. 8 shows yet another attachment, this being a sander.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

By referring firstly to FIG. 1, a power tool shown generally as (2)includes a body portion (4) formed from two halves of a plasticsclamshell. The two halves (6,8) co-operate together to encapsulate theinternal mechanisms of the power tool, which will be described herebelow. The body portion (4) defines a handle (10) which in use of thetool (2) is grasped by the user. The handle (10) is so shaped to providethe user with easy access to an actuating trigger (12) in the form of apistol grip, which is conventional in the art of power tools. The bodyportion (4) is formed from the two halves of clamshell (6,8) also todefine an opening shown generally as (14), through which batteries (16)for powering the tool may pass. Those skilled in the art will appreciatethat the choice of batteries for powering the tool (2) depends upon thework which the tool is required to undertake. The batteries per se formno part of the present invention and so will not be described in anymore detail herein.

At the opposite end of the body portion (4) from the battery opening(14) the two halves of the clamshell (6,8) define an opening (18)through which an output spindle (20) of a motor (22) housed within thebody portion (4) (and shown in more detail in FIG. 2) is mounted.

By referring now also to FIGS. 2 and 3, the internal mechanism of thetool (2) will be described in more detail.

In FIG. 2 it will be understood that the half clamshell (6) has beenremoved for clarity. It can be seen that through the battery opening(14) a pair of batteries (16) have been passed and are electricallycoupled via terminals (24) and switch (12) to the motor (22). Thebatteries (16) are retained within their opening (14) by a detentmechanism (26) which can be manually operated in order to allow theremoval of the batteries (16) from the body portion (4).

The motor (22) is selectively coupled to the batteries (16) via theswitch (12) in conventional manner. On activation of the switch (12) theuser selectively couples the motor (22) to the battery (16) therebyenergising the motor (22) which in turn provides a rotational force uponthe output spindle (20). In example shown the output spindle (20) hasconnected thereto a cog for reasons which will become apparenthereinafter.

As is conventional in the art of power tools the motor (22) is providedwith a forward/reverse switch (28) the operation of which determines thesense of rotation of the output spindle (20).

Whilst remembering of course that the half clamshell (6) is not shown inFIG. 2, although the motor (22) is mounted within the body portion (4),a plurality of ribs (30) actually provide support to the motor (22)within the body portion (4). The ribs (30) can be seen more clearly fromFIGS. 2 and 3. It is important to note that in the example shown inthese figures, the foremost rib (labelled 30(a)) does not actuallycontact the motor (22) itself, but stops slightly short thereof.

It will be apparent that due to the foremost rib (30(a)) not directlycontacting the motor (22) itself, that therefore the motor (22) has aslight degree of movement within its mounting position provided by theplurality of ribs (30). It will also be apparent to those skilled in theart that any one or ones of the combination of the plurality of ribs(30) may stop short of directly contacting the motor (22). The directcontact between the ribs (30) and the motor (22), when it does occur,needs to be rigid thereby to provide a good degree of support to preventthe motor (22) moving at this point of contact. Where the rib (30(a)) isdeliberately designed to stop short of and therefore not form any director rigid contact with the motor (22), then this permits for movement ofthe motor (22) relative to the rib (30).

Because in the example shown the foremost rib (30 (a)) allows a smalldegree of movement of the motor (22) adjacent thereto, it will beapparent that the output spindle (20) will thus have a slight degree ofmovement or “play”. This degree of “play” occurs in a plane defined byan orthogonal set of axis (conventionally termed x-y). The x-y axiswithin which the spindle (20) is free to have a limited degree ofmovement is shown more clearly in FIG. 5.

Referring now particularly to FIGS. 4 and 6 in addition to all otherFIGS. 1 to 3 and 5, it can be seen that a power tool (2) has hadpresented thereto an attachment member (32), in this example adrill/driver mechanism (32) for driving a drill bit. It can be seen thatthe drill/driver mechanism (32) is presented to the body portion (4) atthe opening (18) for the output spindle (20). The outer periphery of thedrill/driver mechanism (32) is shaped so as to co-operate within theopening and mate with the outer periphery of the body portion (4). Aplate member (100) defining a circular hole is formed from the bodyportion (4) within the opening (18). The plate member (100) is arrangedto have a diameter substantially the same as the diameter of the outerperiphery of the foremost tapered armular flange (102) formed on thedrill/driver mechanism (32). Due to the substantial matching of thesediameters, on presentation of the drill/driver mechanism (32) to theopening (18), the insertion of annular flange (102) into plate member(100) the former will be accurately located within the latter. The taperon the front face of flange (102) serves to aid the accurate locationnecessary. As the drill/driver mechanism (32) is brought into position atapered protrusion (34) thereof abuts against a pivotally moveablerelease mechanism (36). When this occurs the right-hand side of thepivotal release mechanism (36) moves down as one views FIG. 4, and theleft-hand side moves up thereby allowing the projecting peg (38) to beremoved from its previously biased position wherein it held the switch(12) permanently open. This provides a form of safety release mechanismwhich prevents accidental actuation of the switch (12) until such timesas the attachment member, or, as in this example, the drill/drivermechanism (32) is in position.

The attachment member (32) has a driven spindle (40) to which is coupledat its end a female cog member (42) which is designed to engage with themale cog on the output spindle (20) of the motor. It will be appreciatedthat when the male and female cogs of the output spindle (20) and thedriven spindle (40) mate together, then actuation of the motor (22) willcause simultaneous rotation of the output spindle (20) and the drivenspindle (40) thereby rotating the head (44) of the drill/drivermechanism (32).

It is the presentation of the drill/driver mechanism (32) to the opening(18) of the body portion (4) which requires a more detailed descriptionof the movement of the motor (22) within its plurality of mounted ribs(30). As the motor (22) axis is free to conically pivot slightly aboutits rear mounting portion defined by those of the plurality of ribs (30)which sit in rigid direct contact with the motor, this therefore allowsan automatic alignment to occur between the axis of rotation of themotor spindle (20) and the axis of rotation of the driven spindle (40).If this were not the case, i.e. if the motor were not free to moveslightly, then on presentation of the drill/driver mechanism (32) to theopening (18), there will be no guarantee of an accurate axial alignmentof both the motor (22) and its output spindle (20) for the drill/drivermechanism (32) and its driven spindle (40).

It will be apparent that the motor (22) is formed in circularcross-section this is chosen as being advantageous for allowing the ribs(30) of the plurality thereof to be shaped so as to accommodate themotor (22) more easily. There is no necessity for the motor (22) to havea circular cross-section or indeed the drill/driver mechanism (32) ortheir respective spindles (20,40).

The ribs (30) of the plurality thereof have been formed from theplastics material of the clamshell halves (6,8). If desired the ribs(30) could be formed from separate members such as metal or otherplastics members glued or otherwise stuck to the clamshell halves (6,8).

Referring now briefly to FIGS. 6 to 8, different ones of the pluralityof attachment members are shown.

FIG. 6 shows a drill attachment (46) for presenting to the body portion(4) and coupling thereto via the opening (18). FIG. 7 shows a jigsawattachment (48) and FIG. 8 shows a sander attachment (50). Whilst thoseskilled in the art will appreciate that the internal mechanisms of eachof the attachment members (46, 48 and 50) will be different and adaptedto suit the purpose of each attachment member, this is not germane tothe present invention and so will not be described herein. For thepurposes of the present inventions, it is sufficient to appreciate thateach of these attachment members (46, 48 and 50) must be presented andcoupled to the body portion (4) as already herein described.

It will be understood by those skilled in the art that the term “rigid”is intended to cover solid, rather than resilient contact. Thus it wouldbe possible to form the ribs (30) of a resilient material whichpermanently contacted the motor (22), or indeed coat the motor in aresilient material, such as silicone rubber, whilst still remainingwithin the scope of the present invention.

What is claimed is:
 1. A power tool system comprising: a common bodyportion including a housing defining a handle and a motor mounted withinthe housing, the motor having a front end and a rear end and arranged todrive a rotatable drive spindle extending from the front end, thehousing further defining an opening around the rotatable output, themotor mounted within the housing by a plurality of supports spaced alongthe axial length of the motor, a first of the plurality of supportsbeing adjacent one of the front end and the rear end and radially spacedfrom the motor and a second of the plurality of supports being adjacentthe other of the front end and rear end and in direct contact with themotor to preclude radial movement of the motor relative to the secondsupport; a plurality of attachment members each selectively andreleasably attachable to the common body portion, each of the pluralityof attachment members including a working portion driven by a drivenspindle, the driven spindle for engaging the rotatable drive spindle;whereby a small degree of radial movement between the motor relative tothe first of the supports is permitted prior to releasable attachment ofone of the attachment members to the common body portion and said smalldegree of radial movement is precluded upon releasable attachment of oneof the attachment members to the common body portion.
 2. A power toolaccording to claim 1 wherein at one end of the axial length of the motora plurality of supports make rigid contact therewith and at the otherend of the axial length of the motor at least one of the supports of theplurality is spaced from the motor thereby allowing the motor to pivotabout a point at which it is in rigid contact with the said supports. 3.A power tool according to claim 2 wherein the other end of the axiallength of the motor is the output end of the motor.
 4. A power toolaccording to claim 1 wherein the motor, at either end of its axiallength, is formed in circular cross-section and the supports of theplurality are found therearound.
 5. A power tool according to claim 1wherein the plurality of supports is formed from, or integrally with,the body portion itself.
 6. A power tool according to claim 1 whereinthe body portion is formed in two halves, which two halves come togetherand thereby encapsulate the motor therewithin.
 7. A power tool accordingto claim 1 wherein movement of the motor within the housing relative toa selected one of the plurality of attachment members prevented when theselected one is attached to the common body portion.
 8. A power toolaccording to claim 1 wherein the motor is connected to the outputspindle.
 9. A power tool comprising: a tool housing; a motor having agenerally cylindrical body and a rotatable output spindle, the generallycylindrical body having a front end and a rear end, the rotatable outputextending from the front end; a tool head releasably attachable to thetool housing, the tool head including a driven spindle for engagementwith the rotatable output spindle; and a plurality of ribs spacedaxially along a length of the motor for supporting the motor, a firstrib of the plurality of ribs disposed adjacent a front end of the bodyand defining at least a portion of a circular opening with a rigiddiameter slightly larger than a diameter of the generally cylindricalbody such that the rigid diameter is radially spaced from and allows asmall degree of radial movement of the motor relative to the first ribin any direction substantially perpendicular to the length of the motorprior to releasable attachment of the tool head to the tool housing anda second rib of the plurality of ribs in direct contact with the motorto preclude radial movement of the motor relative to the second rib,said small degree of radial movement of the motor relative to the firstrib being precluded upon releasable attachment of the tool head to thetool housing.
 10. The power tool of claim 9, wherein the first rib isdisposed adjacent an end of the generally cylindrical body.
 11. Thepower tool of claim 10, wherein the driven spindle axially extends fromthe end of the cylindrical body.
 12. The power tool of claim 9, whereina second rib of the plurality of ribs rigidly contacts the generallycylindrical body.
 13. The power tool of claim 12, wherein the pluralityof ribs permit the motor to conically pivot slightly about a rearmounting portion defined by the second rib.
 14. The power tool of claim9, wherein the tool housing includes first and second clam shell halvesintegrally formed to include the plurality of ribs.
 15. The power toolof claim 9, wherein the tool head is rigidly attachable to the toolhousing such that the small degree of movement of the motor relative tothe first rib is prevented when the tool head is attached to the toolhousing.
 16. The power tool of claim 9, wherein the tool housingincludes a plate member defining a circular opening providing access tothe output spindle and the tool head includes a generally cylindricalportion having an outer diameter substantially equal to an innerdiameter of the circular opening, the cylindrical portion receivedwithin the circular opening when the tool head is releasably attached tothe tool body.
 17. The power tool of claim 16, wherein the cylindricalportion includes a front face having a taper.
 18. The power tool ofclaim 16, wherein the driven spindle is concealed within the cylindricalportion of the tool head.
 19. The power tool of claim 16, wherein theoutput spindle is disposed completely within the tool housing andcompletely behind the plate.
 20. The power tool of claim 9, wherein thepower tool is a hand-held power tool.
 21. The power tool of claim 9,wherein the tool body defines a handle portion.
 22. A power toolcomprising: a tool housing; a tool head removably attached to the toolhousing; and a motor including a generally cylindrical body having afirst end and a second end, the motor further including a rotatableoutput spindle extending from the second end, the motor disposed withinthe tool housing, the first end radially supported directly by the toolhousing and the second end radially supported directly by the tool headsuch that the first end is radially fixed within the tool housing,rotatable output spindle is radially movable prior to releasableattachment of the tool head to the tool housing, and the tool headprecludes radial movement of the rotatable output spindle uponreleasable attachment of the tool head to the tool body.
 23. The powertool of claim 22, further comprising a plurality of ribs spaced axiallyalong a length of the motor for supporting the motor, a first rib of theplurality of ribs defining at least a portion of a circular opening witha rigid diameter slightly larger than a diameter of the generallycylindrical body such that the rigid diameter allows a small degree ofmovement of the motor relative to the first rib in any directionsubstantially perpendicular to the length of the motor prior toreleasable attachment of the tool head to the tool housing.
 24. Thepower tool of claim 23, wherein a second rib of the plurality of ribsrigidly contacts the generally cylindrical body.
 25. The power tool ofclaim 23, wherein the tool housing includes first and second clam shellhalves integrally formed to include the plurality of ribs.
 26. The powertool of claim 23, wherein the plurality of ribs permit the motor toconically pivot slightly about a rear mounting portion defined by thesecond rib.
 27. The power tool of claim 23, wherein the tool housingincludes a plate member defining a circular opening providing access tothe output spindle and the tool head includes a generally cylindricalportion having an outer diameter substantially equal to an innerdiameter of the circular opening, the cylindrical portion receivedwithin the circular opening when the tool head is releasably attached tothe tool body.